Electric shutter device provided with an electric self-timer

ABSTRACT

An electric shutter device wherein an armature lever is attracted by an electromagnet by making a large current flow to the electromagnet only when the operation of a self-timer ends so that a normal exposure operation may be thereby started in order to minimize the power consumption during the operation of the electric self-timer. This electric shutter device is provided with a pair of shutter blades which are also diaphragm blades, a closing drive plate engageable with the armature lever to control the opening and closing of the shutter, an exposure time controlling circuit controlling the energizing time of the electromagnet to determine a proper exposure time, an exposure warning circuit and a flash controlling circuit.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to shutters for photographic cameras andmore particularly to an electric shutter provided with an electricself-timer.

(b) Description of the Prior Art

The electric shutter device having an electric self-timer built in it isalready known. In this kind of known electric shutter device, there area type wherein are provided an electromagnet for controlling theoperation of the self-timer and an electromagnet for controlling theexposure operation and a type wherein the operation of the self-timerand the exposure are controlled with a single electromagnet. However,either of these types is so formed as to make a comparatively largenormal current flow to the electromagnet during the operation of theself-timer and therefore the power consumption is so high that it hasbeen necessary to use a current source battery of a comparatively largecapacity. Further, in such known type, as the operation time of theself-timer is fixedly predetermined, the self-timer device has not beenable to be utilized for the means of correcting the mechanical operationdelay of the shutter mechanism or for the compensating means forpreventing the operation of the reflecting mirror in a single-lensreflex camera from influencing the exposure controlling operation.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an electric shutterdevice provided with an electric self-timer wherein the structure iscomparatively simple, the shift from the end of the self-timer operationto the beginning of the exposure operation can be positively made andthe electric power consumed during the entire operation may becomparatively small.

According to the present invention, this object is attained by formingthe electromagnet for controlling the exposure time so as to work alsowhen the operation of the self-timer ends, limiting the current flowingto the electromagnet to the required minimum during the operation of theself-timer and starting the exposure operation by making a large currentinstantaneously flow to the electromagnet only when the operation of theself-timer ends.

According to a preferable formation of the present invention, theoperation of the self-timer is started positively by a member started bythe release operation and the self-timer operating time shortened by theswitching operation is so made as to be able to serve as an adjustingtime to make the various functions of the camera able to be madepositively and stably.

This and other objects of the present invention will become moreapparent during the course of the following detailed description andappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view showing basic mechanism parts of a shutterdevice according to the present invention as cocked;

FIG. 2 is an elevational view showing the correlation of a pair ofshutter blades;

FIG. 3 is an elevational view of the case that the shutter shown in FIG.1 is opened;

FIG. 4 is an elevational view showing the shutter shown in FIG. 1 as theexposure ends;

FIG. 5 is a side view showing the correlation of a closing drive plateand a plate spring member;

FIGS. 6 to 10 are elevational views showing respectively differentoperating positions of the shutter opening and closing mechanism partsat the time of flash photographing;

FIG. 11 is the same elevational view as in FIG. 1, showing an embodimentin which self-timer controlling elements are incorporated in the shutterdevice shown in FIG. 1;

FIG. 12 is an elevational view of the shutter device shown in FIG. 11 inthe case that the self-timer is in operation;

FIG. 13 is an elevational view in the case that the shutter device shownin FIG. 11 is opened;

FIG. 14 is an elevational view showing the shutter device shown in FIG.11 as the exposure ends;

FIG. 15 is a fragmental elevational view in the case that the self-timermechanism is set;

FIG. 16 is a fragmental elevational view in the case that the self-timermechanism is reset;

FIG. 17 is a fragmental elevational view in the case that the releaselocking mechanism is inoperative;

FIG. 18 is a fragmental elevational view in the case that the releasinglocking mechanism is in operation;

FIGS. 19 to 24 are wiring diagrams showing embodiments in which theshutter controlling circuit parts are respectively different; and

FIG. 25 is a wiring diagram showing an example of battery checkingcircuit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

First, with reference to FIGS. 1 to 9, reference numeral 1 indicates ashutter plate which forms an exposure aperture 1a and light receivingwindow 1b and has pins 1d, 1e, 1f, 1g, 1h and 1i erected on it. 2indicates a release plate which forms slots 2a and 2b fittingrespectively the pins 1c and 1d, forms a bend 2c, has a pin 2d erectedon it and is biased upward by a spring 3. Reference numeral 4 indicatesa closing drive plate which forms slots 4a and 4b fitting respectivelythe pins 1c and 1e, forms arms 4c and 4d, a slope 4e and a flat surface4f, has a pin 4g erected on it and is biased rightward by a spring 5connected between the pins 1e and 4g. Reference numeral 6 indicates aplate spring member which is secured on the closing drive plate 4 byscrews 6a and 6b, forms bends 6c and 6d projecting on the back surfaceside of the closing drive plate 4 at both ends as clearly shown in FIG.4 and is inclined along the lower end edges 6c' and 6d' of therespective bends 6c and 6d. The bend 6c is engageable with the bend 2cof the release plate 2. Reference numeral 7 indicates a shutter releaselever which is pivoted to a shaft 8, forms arms 7a and 7b engageablewith the pin 1f, forms another arm 7c, is bent at the tip 7a' of the arm7a so as to be positioned within the moving track of the bend 6d and isbiased clockwised by a spring 9 so that the arm 7 may engage in contactwith the pin 1f. 10 indicates an opening and closing lever which isborne on a shaft 11, has an arm 10a engageable with the arm 7c and has anonconductive pin 10b, a projection 10c and pins 10d, 10e, 10f and 10g.12 indicates a conductive ring fitted to the pin 10b. 13 indicates aspring serving also as a lead wire, connected between the pin 1i andconductive ring 12 and biasing the opening and closing lever 10counterclockwise. The arm 4d of the closing drive plate 4 is engageablewith the conductive ring 12 and projection 10c of the opening andclosing lever 10 so that a flash synchronizing switch may be formed ofthe arm 4d and conductive ring 12. Reference numeral 14 indicates ashutter blade which is also a diaphragm blade shown as one of a set oftwo, forms slots 14a and 14b fitting respectively the pins 1g and 1h anda slot 14c fitting the pin 10d and forms a shutter opening 14d, a firstopening 14e which leads the light from an object to be photographed todetect the brightness of the object and a second opening 14f which leadsthe light from the object to determine an exposure time. As shown inFIG. 2, the other shutter blade 14' is so formed that, when the firstopening 14'e coincides with the opening 14e of the shutter blade 14 (atthe time of the cocked state), the shutter opening 14'd and secondopening 14'f may be positioned symmetrically on the right and leftrespectively with those of the shutter blade 14. Further, the slot 14'ccorresponding to the slot 14c fits the pin 10e. A later described lightreceiving element is arranged as opposed to the light receiving window1b and can receive the light of the field to be photographed through theopening 14e or 14f. Reference numeral 15 indicates an armature leverwhich is pivoted to a shaft 16, forms a bend 15a capable of locking thearm 4c and another bend 15b and has a pin 15c erected on it. Referencenumeral 17 indicates an armature borne on the bend 15b by a pin 18.Reference numeral 19 indicates a holding lever which is borne on theshaft 16, has a pin 19a engageable with slope 4e and flat surface 4ferected on it, forms an arm 19b engaging with the pin 15c and is biasedclockwise by a spring 20. Reference numeral 21 indicates a spring hungbetween the armature lever 15 and holding lever 19 and acting so thatthe pin 15c and arm 19b may engage with each other. Reference numeral 22indicates a flash photographing opening regulating lever which is borneon a shaft 23, forms a cam surface 22a engageable with the pin 10g, hasa pin 22b movable by a distance adjusting member of a camera notillustrated and is biased clockwise by a spring 24. Further, an upperbase plate and lower base plate not illustrated are set at a slightspacing above and below the shutter blade 1. The shutter blade 14 isarranged between the lower base plate and shutter plate 1. The openingregulating lever 22 is arranged on the back side of the lower base plateand the other members are arranged between the shutter plate 1 and theupper base plate. Therefore, the pins 10d and 10e of the opening andclosing lever 10 project on the back side of the shutter plate 1 throughit and the pin 10g projects to the back side of the lower base platethrough the shutter plate 1 and lower base plate. By the way, slotsallowing the motions of the pins 10d, 10e and 10g are formed on theshutter plate 1 and lower base plate but are omitted in the drawing.Further, the shutter plate 1, closing drive plate 4 and opening andclosing lever 10 may be formed integrally with the pins and shaftslocated on them with a resin or the like. In such case, it will benecessary to make electric connection possible to pasting a conductivepiece on the surface to be engaged with the conductive ring 12 of thearm 4d of the closing drive plate 4. Further, reference numerals 102,114 and 117 indicate switches and an electromagnet of a later describedcontrolling circuit. The electromagnet 117 is supported by a part notillustrated raised from the shutter plate 1 on the back side of theupper base plate so as to be arranged to be spaced from the surface ofthe shutter plate 1 and to be opposed to the armature 17.

The formation of the shutter controlling circuit shown in FIG. 19 shallbe explained in the following as related with the above describedshutter mechanism. Reference numeral 101 indicates a current sourcebattery earthed at the minus (-) pole. Reference numeral 102 indicates acurrent source switch opened and closed by the pin 2d of the releaseplate 2. Reference numeral 103 indicates such light receiving element asa photoelectromotive element earthed at the anode and connected at thecathode to a reversing input terminal (-) of an amplifying circuit 104.105 indicates a logarithmic compression diode connected at the cathodeto the reversing input terminal (-) of the amplifying circuit 104 and atthe anode to the output terminal of the amplifying circuit. Referencenumeral 106 indicates a reference voltage generating circuit. Referencenumeral 107 indicates a window comparator. The reversing input terminal(-) 107a is connected to the output terminal of the amplifying circuit104. Nonreversing input terminals (+) 107b and 107c are connectedrespectively to output terminals 106a and 106b of the reference voltagegenerating circuit. Reference numerals 108 and 109 indicatesover-exposure warning and camera-shake warning LED's (which may be lampsor the like) respectively connected between the output terminals 107dand 107e of the comparator 107 and the plus pole of the current sourcebattery 101 through the current source switch 102. Reference numeral 110indicates an exposure time controlling capacitor which can be connectedat one end to the plus pole of the current source battery 101 throughthe current source switch 102 and at the other end to a collector of atransistor 112 or a resistor 113 through a switching switch 111. Thebase of the transistor 112 is connected to the output terminal of theamplifying circuit 104. Reference numeral 114 indicates an exposure timemeasurement beginning switch which is connected in parallel with thecapacitor 110 and can be opened and closed by the pin 10f of the openingand closing lever 10. Reference numeral 115 indicates a comparatorconnected at the nonreversing input terminal (+) to the output terminal106c of the reference voltage generating circuit 106 and at thereversing input terminal (-) to the other end of the capacitor 110.Reference numeral 116 indicates an amplifying circuit connected to theoutput terminal of the comparator 115. The electromagnet 117 isconnected between the amplifying circuit 116 and the plus pole of thecurrent source battery 101 through the current source switch 102.Reference numeral 118 indicates an amplifying circuit connected at thenonreversing input terminal (+) to the output terminal 106d of thereference voltage generating circuit 106 and at the output terminal tothe nonreversing input terminal (+) of the amplifying circuit 104.Reference numeral 119 indicates a variable resistor connected betweenthe output terminal and the reversing input terminal (-) of theamplifying circuit 118. Reference numeral 120 indicates a resistorconnected at one end to the joint of the reversing input terminal (31)of the amplifying circuit 118 and the variable resistor 119 and earthedat the other end.

The operation of this embodiment shall be explained in the followingwith reference to FIGS. 1 to 10 and 19.

First of all, the warning operation shall be described. When the releaseplate 2 is pushed down against the tension of the spring 3, the currentsource switch 102 will be closed by the displacement of the pin 2d and avoltage will be fed to the respective parts of the circuit. At thistime, the light receiving element 103 will be irradiated with the lightfrom the object to be photographed passing through the light receivingwindow 1b and opening 14e and therefore a photoelectric current i willbe generated and will be amplified by the amplifying circuit 104. As theamplifying circuit 104 has the logarithmic compression diode 105connected between the output terminal and reversing input terminal (-)so as to return, a voltage proportional to the logarithm of thephotoelectric current i will be generated at the output terminal andwill be given to the reversing input terminal (-) 107a of the windowcomparator 107. Here, if this voltage is higher than the referencevoltage for the over-exposure warning given to the nonreversing inputterminal (+) 107b from the output terminal 106a of the reference voltagecircuit 106, only the LED 108 connected to the output terminal 107d willbe lighted. If it is lower than the reference voltage for thecamera-shake warning given to the nonreversing input terminal (+) 107cfrom the output terminal 106b, only the LED 109 connected to the outputterminal 107e will be lighted. In case the voltage given to thereversing input terminal 107a is between the above mentioned bothreference volatages, that is, in case the brightness of the object to bephotographed is in the range in which the proper exposure is possibleneither of the LED's 108 and 109 will be lighted. By the way, the signalfor the camera-shake warning is so made as to be reversed within thewindow comparator 107.

Now the automatic photographing shall be described. In this case, theswitching switch 111 will be connected to the terminal 111a side asillustrated by a switching member for switching automatic photographingand flash photographing with each other provided on the camera body notillustrated, the opening regulating lever 22 will remain in the positionin FIG. 1 without being moved by the distance adjusting member and thecam surface 22a will be out of the moving track of the pin 10g of theopening and closing lever 10. By the way, this switching mechanism canbe also operatively connected with the operation of fitting the flashingdevice to the camera body or the operation of making the flashing devicehop up from the camera body. As already explained, in the initial stageof the shutter release to check whether the brightness of the object tobe photographed is in the proper range, the switch 114 will be closed,the reversing input terminal (-) of the comparator 115 will be placed onthe potential level of the plus pole of the current source battery 101,the output terminal will be placed on the "L" level and therefore theelectromagnet 117 will be excited from the beginning of the closing ofthe current source switch 102. Therefore, as the armature 17 isattracted by the electromagnet 117, the armature lever 15 will be heldin the stage in FIG. 1. When the release lever 2 is further pushed downfrom this state, the bend 2c will disengage from the bend 6c of theplate spring member 6. As a result, the closing drive plate 4 will moverightward under the tension of the spring 5 and will be once stoppedwhile the arm 4c is in contact with the bend 15a of the armature lever15 as shown in FIG. 3. Until the closing drive plate 4 reaches thisposition, the slope 4e will push the pin 19a to rotate the holding lever19 counterclockwise against the tension of the spring 20 to tension thespring 21. Further, the bend 6c of the plate spring member 6 will engagewith the bend 2c of the release lever 2 to prevent the return of therelease lever 2 and keep the current source switch 102 closed. On theother hand, the bend 6d will push the bend 7a' to rotate the shutterrelease lever 7 counterclockwise against the tension of the spring 9. Bythe counterclockwise rotation of the lever 7, the arm 7c will bedisengaged from the arm 10a, therefore the opening and closing lever 10will be rotated counterclockwise by the tension of the spring 13, theshutter blade 14 will be moved rightward by the pin 10d (the othershutter blade 14' will be moved leftward by the pin 10e) and the switch114 will be opened by the displacement of the pin 10f. With the movementof the shutter blades 14 and 14', first of all, the first opening 14ewill retreat from the light receiving window 1b to once shield it.However, at this time, the switch 114 will be already opened andtherefore the capacitor 110 will begin to be charged with a current of asize corresponding to that of the dark current from the light receivingelement 103. Then the second opening 14f will first begin to open thelight receiving window 1b and a little later the shutter opening 14dwill open the exposure aperture 1a. By such preliminary charging of thecapacitor 110 by the dark current from the light receiving element 103and the preceding opening of the light receiving window 1b by theopening 14f, the so-called mechanical delay will be corrected. Then, bythe increase of the area of the opening 14f corresponding to theincrease of the area of the shutter opening 14d, the amount of the lightfrom the object to be photographed irradiating the light receivingelement 103 will be gradually increased, the current proportional to theamount of this incident light will flow into the collector of thetransistor 112 and the capacitor 110 will further continue to thecharged. Thus the potential of the reversing input terminal (-) of thecomparator 115 will gradually lower. Here, if a light receiving elementwherein the photoelectric current becomes larger in direct proportion tothe brightness of the object to be photographed is used, the amount ofthe collector current of the transistor 112 will be proportional to theamount of the photoelectric current and therefore the amount of lightwill be integrated in the capacitor 110 as a result. Further, as theopenings 14d and 14f are formed on the same member and are substantiallysimilar in the shape, it can be said that the integrated amount of thephotoelectric current and the amount of the light reaching the filmsurface are directly proportional to each other. Therefore, if a fixedpotential is given to the nonreversing input terminal (+) of thecomparator 115 from the output terminal 106c of the reference voltagegenerating circuit 106, this potential will give a reference of theamount of exposure to the film surface so that the amount of exposuregiven actually to the film surface may be controlled by the comparisonwith the potential corresponding to the integrated amount of thephotoelectric current. With the progress of the charging of thecapacitor 10, when the potential of the reversing input terminal (-) ofthe comparator 115 becomes lower than the potential of its nonreversinginput terminal (+), the comparator 115 will reverse, its output terminalwill be on the "H" level and therefore the electromagnet 117 will bedemagnetized. As a result, the armature lever 15 will be rotatedcounterclockwise by the spring 21 and will disengage the bend 15a fromthe arm 4c. Therefore, the closing drive lever 4 will be moved furtherrightward by the tension of the spring 5 as shown in FIG. 4. With thisrightward movement of the closing drive lever 4, the arm 4d will firstcontact the conductive ring 12 and will rotate the opening and closinglever 10 clockwise against the tension of the spring 13. In the courseof the right-ward movement, the arm 4d of the closing drive lever 4 willengage in contact with the nonconductive projection 10c instead of theconductive ring 12 and will rotate the opening and closing lever 10further clockwise. Therefore, as a result, the shutter blade 14 willclose the exposure aperture 1a in the course of opening the exposureaperture 1a with the opening 1d or when the exposure aperture 1a isfully opened. Further, by the clockwise rotation of the opening andclosing lever 10, the movable contact piece of the switch 114 will bepushed and moved by the pin 10f so as to be closed and therefore thecapacitor 110 will be discharged. Further, the bend 6c of the platespring member 6 will be disengaged from the bend 2c and therefore therelease lever 2 will be returned upward by the tension of the spring 3to open the current source switch 102 with the pin 2d. On the otherhand, the bend 6d will be disengaged from the bend 7a' and therefore theshutter release lever 7 will be rotated clockwise by the tension of thespring 9 until the arm 7a contacts the pin 1f and the arm 7c will bepresent within the counter-clockwise track of the arm 10a of the openingand closing lever 10. The shutter is cocked by moving the closing driveplate 4 leftward against the tension of the spring 5. That is to say,when the closing drive plate 4 is moved leftward from the position inFIG. 4, the plate spring member 6 will ride over the bend 2c of therelease lever 2 through the slope 6c (FIG. 5) of the bend 6c, will rideover the bend 7a of the shutter release lever 7 through the slope 6d' ofthe other bend 6d, will run over them and will then return and the bend6c will engage with the bend 2c. On the other hand, with the leftwardmovement of the closing drive plate 4, the pin 19a will move to theposition of the slope 4e from the flat surface 4f as a result.Therefore, the holding lever 19 will be rotated clockwise with thearmature lever 15 by the spring 20, the bend 15a will be present withinthe moving track of the arm 4c and the armature 17 will contact theelectro-magnet 117. As a result, all the members will return to thestate in FIG. 1.

Now the flash photographing shall be described. By the switchingoperation to the flash photographing, the switching switch 111 (FIG. 19)will be connected to the terminal 111b, the resistor 113 instead of thetransistor 112 will be connected to the capacitor 110 and the openingregulating lever 22 for flash photographing will become able to beoperated by the distance adjusting member (not illustrated) of thecamera through the pin 22b. Now, if the flash opening regulating lever22 is rotated counterclockwise to the state in FIG. 6 as interlockedwith the manual operation of the distance adjusting member, by the abovedescribed shutter releasing operation, the opening and closing lever 10will be rotated counterclockwise until the pin 10g contacts the camsurface 22a and the exposure aperture 1a will be opened to be of a sizecorresponding to the photographing distance by the opening 14d of theshutter blade 14. When the electromagnet 117 is demagnetized after thelapse of a fixed delay time determined by the capacitor 110 and resistor113, the same as is described above, the closing drive plate 4 will moverightward and the exposure aperture 1a will be closed by the shutterblade 14. Also, as shown in FIG. 7, when the arm 4d for beginning theclosing operation of the shutter blade 14 contacts the conductive ring12, the flash synchronizing switch will be closed and the flashingdevice will flash in the position of the maximum opening of the shutterblade fitted to the photographing distance. By the way, as shown in FIG.4, at the final point of the shutter closing operation, the arm 4d willbe separated from the conductive ring 12 and will be engaged with thenonconductive projection 10c and therefore the flashing device will notmis-flash.

FIG. 8 shows an embodiment modified so that the flashing device mayflash at the point when the opening and closing lever 10 contacts theflash opening regulating lever 22. That is to say, on the opening andclosing lever 10, the pin 10b is removed, a conductive ring 12' isfitted to the pin 10g, the spring 13 is hung at one end on theconductive ring 12', the flash opening regulating lever 22 is made aconductive member and a flash synchronizing switch is formed of the camsurface 22a and conductive ring 12'.

FIGS. 9 and 10 show an embodiment wherein the above mentioned flashingdevice is so modified as to make the flash photographing in the daytimepossible. That is to say, on the opening and closing lever 10, theconductive ring 12 is fitted to the pin 10b, the conductive ring 12' isfitted also to the pin 10g and a spring 13' serving as a lead wire ishung also between the conductive ring 12' and pin 1j. A flashsynchronizing switch by the conductive ring 12 and arm 4d and a flashsynchronizing switch by the conductive ring 12' and cam surface 22a areconnected in parallel with each other. The exposure time is made to beautomatically controlled in response to the brightness of the object tobe photographed in the same manner as is already explained by thecircuit including the light receiving element 103, capacitor 110 andtransistor 112. Therefore, in case the area of the shutter openingdetermined in response to the photographing distance is smaller than thearea of the shutter opening determined by the brightness of the objectto be photographed, as shown in FIG. 9, when the conductive ring 12'contacts the cam surface 22a, the flashing device will flash and theexposure time will be determined by the natural light and the auxiliarylight by the flashing device. In case the area of the shutter openingdetermined in response to the photographing distance is larger than thearea of the shutter opening determined by the brightness of the objectto be photographed, as shown in FIG. 10, when the arm 4d contacts theconductive ring 12, the flashing device will flash. Thus the shutteropening will become the smaller diaphragm aperture to be determined inresponse to the brightness of the object to be photographed or thephotographing distance.

By the way, FIG. 7 has been described as showing the operation of themechanism after the state in FIG. 6 is reached. However, with only theflash synchronizing switch of a set of the arm 4d and conductive ring12, flash photographing in the daytime can be made possible. In theabove described explanation, FIG. 6 shows the state where the shutteropening is determined in response to the photographing distance and FIG.7 shows the state where the shutter opening is determined in response tothe brightness of the object to be photographed. In this case, the timeof flashing of the flashing device will coincide with the time ofbeginning the closing operation of the shutter blade 14 but the shutteropening will invariably become the smaller diaphragm aperture of thediaphragm apertures to be determined by the brightness of the object tobe photographed or the photographing distance. The displacement of theflash opening regulating lever 22 can be made to be controlled not onlyby the distance information but also by the compound information of theguide number information and/or film sensitivity information. Further,in the controlling circuit in FIG. 19, if the variable resistor 119 isvaried, the potential of the nonreversing input terminal (+) of theamplifying circuit 104 will vary and the voltage of the output terminalwill be able to be shifted. Therefore, such photographing information asthe film sensitivity and/or F value can be electrically introduced bythe variable resistor 119.

Next, the shutter controlling circuit in which the circuit forpreventing the mis-indication of the exposure warning and the maximumexposure time regulating circuit are incorporated shall be describedwith reference to FIG. 20. Reference numeral 121 indicates a comparatorin which the nonreversing input terminal (+) is connected to the outputterminal of the amplifying circuit 104 and the reversing input terminal(-) is connected to the output terminal 106e of the reference voltagecircuit 106. Reference numerals 122, 123 and 124 indicate respectively acapacitor, resistor and inverter forming a differentiating circuit. Thecapacitor 122 is connected at one end to the output terminal of theinverter 124. The resistor 123 is connected at one end to the plus poleof the current source battery 101 through the current source switch 102.Reference numeral 125 indicates a latch circuit in which such circuit asa flip-flop circuit is used, a setting input end (S) is connected to theoutput terminal of the inverter 124 forming the differentiating circuitand a reversing output terminal (Q) is connected to the gate inputterminal (G) 107f of the window comparator 107. Reference numerals 126and 127 indicate a capacitor and resistor forming a delaying circuit forregulating the maximum exposure time. The capacitor 126 is connected atone end to the plus pole of the current source battery 101 through thecurrent source switch 102. The resistor 127 is earthed at one end.Reference numeral 128 indicates a transistor which is connected inparallel with the capacitor 126 and is connected at the base to thenonreversing output terminal (Q) of the latch circuit 125. 129 indicatesa converter in which the reversing input terminal (-) is connected tothe joint of the capacitor 126 and resistor 127 and the nonreversinginput terminal (+) is connected to the output terminal 106f of thereference voltage circuit 106. 130 indicates an OR gate in which oneinput terminal a is connected to the output terminal of the comparator129, the other input terminal b is connected to the output terminal ofthe comparator 115 and the output terminal is connected to one end ofthe electromagnet 117 through the amplifying circuit 116.

The operation of this embodiment shall be described in the following.Just before the beginning of the opening operation of the abovedescribed shutter blade 14, the light receiving element 103 will be onceshielded from the light of the field to be photographed. This state isthe same as of the camera-shake warning. In the shutter controllingcircuit in FIG. 19, the LED 109 will be lighted to make amis-indication. But, in the circuit of this embodiment, when the outputvoltage of the amplifying circuit 104 becomes a voltage corresponding tothe dark current generated when no light is incident upon the lightreceiving element 103, the potential of the nonreversing input terminal(+) of the comparator 121 will become lower than the potential of thenonreversing input terminal (+) given by the output terminal 106e of thereference voltage circuit 106 and therefore the output terminal of thecomparator 121 will reverse to the "L" level from the "H" level. By thisreversal, a negative differentiating pulse will be generated by thedifferentiating circuit. As a result, a positive pulse will be generatedat the output terminal of the inverter 124, the latch circuit 125 willbe set and the reversing output terminal (Q) will reverse to the "L"level from the "H" level. The signal of this "L" level will be given tothe gate input terminal (G) of the window comparator 107, therefore bothoutput terminals 107d and 107e of the comparator 107 will be placed onthe "H" level and the LED's 108 and 109 will be no longer able to belighted. On the other hand, when the nonreversing output terminal (Q) isreversed to the "H" level by setting the latch circuit 125, thetransistor 128 will be interrupted and therefore the capacitor 127 willbe charged in response to the value of the resistor 127. In the initialstate, both output terminals of the comparators 115 and 129 will be onthe "L" level, the output terminal of the OR gate 130 will be on the "L"level and therefore the electromagnet 117 will be excited. However, whenthe output terminal of one comparator 115 or 129 is reversed to the "H"level by the interruption of the transistor 128 and the opening of theswitch 114 by the above described operation, the output terminal of theOR gate 130 will reverse to the "H" level, the electromagnet 117 will bedemagnetized and then the shutter blade 14 will be closed. That is tosay, the maximum exposure time will be regulated by the delay time bythe capacitor 126 and resistor 127 and will be able to be set, forexample, to be 10 seconds or to be 1/30 or 1/15 second so as to cause nocamera-shake. If the resistor 127 is made a variable resistor or aresistor of a type wherein a plurality of resistors of differentresistance values are switched to be used, it will be more effective.When the maximum long time is set to be 1/30 or 1/15 second, a shuttercontrolling circuit effective even at the time of flash photographingwill be able to be made.

A shutter controlling circuit wherein the beginning of the exposure timemeasurement is also electrically controlled shall be described in thefollowing with reference to FIG. 21. Reference numerals 131 and 132indicate respectively a capacitor and variable resistor for forming adelaying circuit for adjusting the time of beginning the exposure timemeasurement. The capacitor 131 is connected at one end to the plus poleof the current source battery 101 through the current source switch 102.The variable resistor 132 is earthed at one end. Reference numeral 133indicates a transistor connected in parallel with the capacitor 131 andconnected at the base to the reversing output terminal (Q) of the latchcircuit 125. 134 indicates a comparator in which the reversing inputterminal (-) is connected to the joint of the capacitor 131 and variableresistor 132 and the nonreversing input terminal (+) is connected to theoutput terminal 106g of the reference voltage circuit 106. Referencenumeral 135 indicates a transistor connected in parallel with thecapacitor 110 instead of the switch 114 in FIGS. 19 and 20 and connectedat the base to the output terminal of the comparator 134 together withthe base of the transistor 128. Reference numeral 136 indicates avariable resistor which is connected at one end to the input terminal106h capable of adjusting the voltage of the output terminal 106g of thereference voltage circuit 106 and is earthed at the other end. In theinitial stage of the shutter release, the reversing output terminal (Q)of the latch circuit 125 will be on the "L" level and the transistor 133will conduct. Therefore, in the comparator 134, the reversing inputterminal (-) will be on the "H" level, the output terminal will beplaced on the "L" level and both transistors 128 and 135 will conduct.When the latch circuit 125 is set as described above and its reversingoutput terminal (Q) reverses to the "H" level, the transistor 133 willbe interrupted and therefore the capacitor 131 will begin to be chargedin response to the value of the variable resistor 132. When thepotential of the reversing input terminal (-) of the comparator 134becomes lower than the potential of its nonreversing input terminal (+)given by the output terminal 106g of the reference voltage circuit 106,the comparator 134 will reverse and its output terminal will be on the"H" level. As a result, the transistors 128 and 135 will be interrupted,the regulation of the maximum exposure time and the measurement of theexposure time will be started and the subsequent operation will be thesame as in the case of the shutter controlling circuit described withreference to FIG. 20. Therefore, by setting the variable resistor 132 tovary the time until the comparator 134 reverses, the mechanical delaytime until the shutter blade actually closes from the time when theelectric signal for closing the shutter blade is generated can beadjusted easily and properly. Further, the same adjustment can be madealso by varying the reference voltage of the nonreversing input terminal(+) of the comparator 134 by replacing the variable resistor 132connected to the reversing input terminal (-) of the comparator 134 witha resistor having a constant resistance value and adjusting theresistance value of the variable resistor 136.

The operation of the shutter according to the present inventionincluding a self-timer device shall be explained in the following withreference to FIGS. 11 to 14 and 22. In this case, on the closing driveplate 4, a hook 4h is further formed and a pin 4i is erected. On thearmature lever 15, a bend 15d is formed instead of the pin 15c and isengaged with the arm 19b of the holding lever 19 on one side. Referencenumeral 25 indicates a timer lever which is borne on the shaft 16, has abend 25a engageable with the hook 4h and an arm 25b engaged with theother side surface of the bend 15d and is biased counterclockwise by aspring 26 somewhat stronger than the spring 20. As a result, in theinitial stage of the shutter release, the armature lever 15 will berotated counterclockwise and the electromagnet 117 will be excited butthe armature 17 will not be attracted and will be separated from theelectromagnet 117. The electromagnet 117 is connected at one end of thewinding to the output terminal 115a of the comparator 115 through theresistor 137 instead of the amplifying circuit 116. Accordingly, as onlya small current restricted by the resistor 137 will flow when thecurrent source switch 102 is closed, the magnetic force will be weak.Reference numerals 138 and 139 indicate respectively a resistor andcapacitor forming a delaying circuit for the self-timer. The resistor138 is connected at one end to the plus pole of the current sourcebattery 101 through the current source switch 102. The capacitor 139 isearthed at one end. Reference numeral 140 indicates a switch which is tostart the operation of the above mentioned delaying circuit, isconnected in parallel with the capacitor 139 and is opened and closed bythe pin 4i of the closing drive plate 4. Reference numeral 141 indicatesa switch for switching to set and reset the self-timer. 142 indicates aresistor connected in series to the switch 141 and very small in theresistance value. This series circuit is connected in parallel with theresistor 138. Reference numeral 143 indicates a comparator in which thereversing input terminal (-) is connected to the output terminal 106i ofthe reference voltage circuit 106 and the nonreversing input terminal(+) is connected to the joint of the resistor 138 and capacitor 139.Reference numerals 144, 145 and 146 indicate respectively a capacitor,resistor and inverter for forming a differentiating circuit. Thecapacitor 144 is connected at one end to the output terminal 143 a ofthe comparator 143. One end of resistor 145 is earthed. 148 indicates acurrent amplifying circuit in which the input terminal is connected tothe output terminal of the inverter 146 and the output terminal isconnected to one end of the electromagnet 117. 149 indicates a NAND gatein which the input terminal is connected to the nonreversing outputterminals 15b and 143b respectively of the comparators 115 and 143.Reference numerals 150, 151 and 152 indicate respectively a capacitor,resistor and inverter for forming a differentiating circuit. Thecapacitor 150 is connected at one end to the output terminal of the NANDgate 149. The resistor 151 is connected at one end to the plus pole ofthe current source battery 101 through the current source switch 102.Reference numeral 153 indicates an "SCR" in which the gate is connectedwith the output terminal of the inverter 152 and is earthed through theresistor 154 and the cathode is earthed. 155 indicates a trigger circuitof an electroflash device connected between the anode and cathode of the"SCR" 153.

The operation of this embodiment shall be explained in the following.

In the case of photographing by using the self-timer, a dial set, forexample, on the camera body not illustrated is rotated to the self-timerposition and opens switch 141. With the operation of the release lever2, the closing drive plate 4 will move rightward but will be oncestopped in the position in which the hook 4h is locked by the bend 25aof the timer lever 25. By the displacement of the pin 4i with thismovement of the closing drive plate 4, the switch 140 will be opened andthe capacitor 139 will begin to be charged through the resistor 138. Inthis state, too, the return of the release level 2 will be prevented andthe current source switch 102 will be kept closed. With the progress ofthe charging of the capacitor 139, after the lapse of the self-timeroperating time, for example of 10 seconds, the potential of thenonreversing input terminal (+) of the comparator 143 will become higherthan the potential of its reversing input terminal (-) given from theoutput terminal 106i of the reference voltage circuit 106, thecomparator 143 will reverse and the output terminal 143a will be on the"H" level. As a result, a positive differentiating pulse will begenerated at the connecting point of the capacitor 145 and resistor 145and a negative pulse will be generated at the output terminal of theinverter 146. Therefore, a negative pulse will be given to theelectromagnet 117 through the current amplifying circuit 148, then alarge current will be made to flow instantaneously through theelectromagnet 117, the magnetic force will increase to attract thearmature 17 and the armature lever 15 and timer lever 25 will be rotatedclockwise against the tension of the spring 26. After the armature 17has been attracted, the current to be supplied to the electromagnet 117becomes small due to the disappearance of the pulse. However, theelectromagnet 117 can hold the armature 17 in the attracted position.The subsequent operation process is as shown in FIGS. 13 and 14. Theoperation order is the same as is described with reference to FIGS. 3and 4 and therefore shall not be explained in detail here.

At the time of ordinary photographing without using a self-timer, theswitch 141 will be closed, the resistor 142 of a small resistance valuewill be connected in parallel with the resistor 138 as a result andtherefore the resistance value of the resistor to be connected to thenonreversing input terminal of the comparator 143 will be smaller thanin the case of only the resistor 138. Therefore, the delay timedetermined by the resistors 138 and 142 and capacitor 139 will becomevery short and the operation of opening and closing the shutter will bemade substantially simultaneously with the operation of the releaselever 2. By the way, in this case, the delay time can be made O butthere is an advantage that, by selecting the delay time to be of aproper value, there can be obtained an accomodation corresponding to thetime required to complete the operation of the mirror and/or automaticdiaphragm mechanism in a single-lens reflex camera or the operation ofthe adjusting mechanism in a camera provided with an automatic focusadjusting mechanism.

Further, in this shutter mechanism, too, the same as in the abovedescribed case, a flash synchronizing switch is formed of the arm 4d ofthe closing drive plate 4 and the conductive ring 12 on the opening andclosing lever 10. In this shutter controlling circuit, an electric flashsynchronizing switch is also incorporated. That is to say, when thecomparator 143 reverses at the time when the operation of the self-timeris completed, one input terminal of the NAND gate 149 will be on the "H"level due to the nonreversing output terminal 143b and the gate will beready to be closed. When the comparator 115 reverses at the time whenthe shutter blade 14 is closed, the other input terminal of the NANDgate 149 will be also on the "H" level due to the nonreversing outputterminal 115b, as a result, the gate 149 will be closed and the outputterminal will be on the "L" level. Therefore, at the same time as apositive differentiating pulse is given to the gate by thedifferentiating circuit, the SCR 153 will conduct and will drive thetrigger circuit 155. When the shutter blade 14 reaches the maximumopening position, the electroflash will be able to be flashed. Further,not only the signal of the output terminal 143b of the comparator 143 asin this embodiment but also the signal generated in response to theshutter opening time by utilizing such latch circuit 125 as in FIG. 20and providing another nonreversing output terminal may be utilized forone input signal of the NAND gate 149.

FIG. 23 shows an embodiment in the case that a well known low constantcurrent circuit C is connected to the electromagnet 117 instead of theresistor 137 in FIG. 22. According to this embodiment, the same as inthe case of FIG. 22, when the current source switch 102 is closed, a lowconstant current will continue to be fed to the electromagnet 117through the low constant current circuit C but, when the self-timeroperation ends, that is, only when the output of the amplifier 148reverses to the "L" level, a large current will be fed to theelectromagnet 117 for a moment. That is to say, as already explained,after the current source switch 102 is closed, until a shutter closingsignal is generated, the output end 115a of the comparator 115 will beplaced on the "L" level and therefore a transistor Q₁ will be offmeanwhile. Therefore, a current based on the voltage divided by aresistor R₁ and diode D₁ will flow between a diode D₂ and the base andemitter of a transistor Q₂. In this case, the voltage between theterminals of the diode D₁ will be kept stable unless the current sourcevoltage V_(cc) reduces extremely. Therefore, in this state, the lowcurrent flowing between the base and emitter of the transistor Q₂ willflow through the electromagnet 117 as a result. When the self-timeroperation thus ends and the output of the amplifier 148 reverses to the"L" level, only for that moment, a large current will flow through theelectromagnet 117 and then a low current will again continue to flow.After the lapse of a proper exposure time, when the output terminal 115aof the comparator 115 reverses to the "H" level to close the shutter,the transistor Q₁ will conduct, therefore the transistor Q₂ will notconduct and the current flowing through the electromagnet 117 will beinterrupted.

FIG. 24 shows an embodiment of the shutter controlling circuit wherein acircuit for preventing the mis-indication of an exposure warning isincorporated in the circuit of FIG. 22. Here the gate input terminal (G)107f of the window comparator 107 is made to be controlled by thereversing output terminal 143c of the comparator 143.

Further, FIG. 25 shows an embodiment wherein a battery checking circuitis formed by using a camera-shake warning circuit. Here referencenumerals 156 and 157 indicate resistors forming a voltage dividingcircuit and briefly showing a circuit giving a reference voltage for thecamera-shake warning by the output terminal 106b of the referencevoltage circuit 106. Reference numerals 158 and 159 indicate resistorsforming a voltage dividing circuit and serving to detect the voltage ofthe current source battery 101. Reference numerals 160 and 161 indicaterespectively a constant current circuit and constant voltage diode usedto set a checking level. 162 indicates a comparator in which thereversing input terminal (-) is connected to the joint of the resistors158 and 159 and the nonreversing input terminal (+) is connected to thejoint of the constant current circuit 160 and constant voltage diode161, 163 indicates a transistor in which the base is connected to theoutput terminal of the comparator 162 and the resistor 157 is connectedbetween the collector and emitter. When the voltage of the currentsource battery 101 is above the checking level, as the potential of thereversing input terminal (-) is higher than the potential of thenonreversing input terminal (+) in the comparator 162, its outputterminal will be "L" and will intercept the transistor 163. Therefore,the battery checking circuit part will be independent of thecamera-shake warning circuit. On the other hand, when the voltage of thecurrent source battery 101 is below the checking level, the output ofthe comparator 162 will be on the "H" level and therefore the transistor163 will conduct. As a result, in the window comparator 107, thenonreversing input terminal (+) will be of the potential of the minuspole of the current source battery, the output terminal 107e will be onthe "H" level and the LED 109 will become unable to be lighted.Therefore, while the current source switch 102 is closed, when theincident light to the light receiving element 103 is shielded, if theLED 109 lights, the voltage of the current source battery 101 will beabove the checking level but, if it does not light, the voltage will beindicated to be below the checking level.

Now, an embodiment wherein the self-timer mechanism is so formed as tobe reset after one exposure operation shall be explained with referenceto FIGS. 15 and 16. A pin 1K is further erected on the shutter plate 1.A projection 25 is further formed on the timer lever 25. Referencenumeral 27 indicates a timer setting lever which is borne on a shaft 28,has pins 27a and 27b for opening and closing the switch 141 erected onit and forms a slot 27c. 29 indicates a timer setting lever which isborne on a shaft 30, is fitted to the slot 27c, has a pin 29a engageablewith the projection 25c erected on it, forms an arm 29b engageable withthe back part of the bend 15d of the armature lever 15 and is biasedclockwise by a spring 31 stronger than the spring 26 (See FIG. 11). FIG.15 shows the self-timer as set. When the armature 17 is attracted by theelectromagnet 117 and the armature lever 15 rotates clockwise to end theself-timer operation, the back part of the bend 15d will be disengagedfrom the arm 29d and therefore the resetting lever 29 will be rotatedclockwise by the tension of the spring 31. By the clockwise rotation ofthe resetting lever 29, the setting lever 27 will be rotatedcounterclockwise through the pin 29a and the projection 25c will bepushed and moved to rotate the timer lever 25 clockwise against itshabit. As a result, the respective elements will be as in FIG. 16, theswitch 141 will be closed and the bend 25a of the timer lever 25 will beheld in the position retreated from the moving track of the hook 4h ofthe closing drive plate 4.

The self-timer mechanism will be set when the setting lever 27 isrotated clockwise by a setting member not illustrated from the state inFIG. 16. That is to say, when the resetting lever 29 is rotatedcounterclockwise against the tension of the spring 31 by the clockwiserotation of the setting lever 27, the back part of the arm 29b engageswith the side surface of the bend 15d and the arm 29b rides over thebend 15d while rotating the armature lever 15 counterclockwise, thestate in FIG. 15 will be made and the setting will be completed. In thisembodiment, the exposure time and self-timer are controlled with oneelectromagnet. However, separate electromagnets may be used. By the way,when the above described resetting mechanism is incorporated, in casethe armature lever 15 is attracted by the electromagnet 117, the loadrotating the timer lever 25 clockwise will be reduced and therefore theattracting operation will be more positive.

Next, the release locking mechanism in the case that the voltage of thecurrent source battery 101 is below the rated value shall be explainedwith reference to FIGS. 17 and 18. A bend 1l as a stopper is furtherformed on the shutter plate 1. A bend 2e is further formed on therelease lever 2. Reference numeral 32 indicates a release locking leverwhich is borne on a shaft 33, can contact the bend 1l and forms an arm32a capable of being present within the moving track of the bend 2e anda bend 32b related with the electromagnet 117, has the base portion 32b'of the bend 32b engaged with one end of the yoke 117b of theelectromagnet 117, has the bent portion 32b" opposed to the side surfaceof a core 117a and is biased clockwise by a weak spring 34.

The operation of this embodiment shall be explained in the following.

When the release lever 2 is pushed down, as described above, the currentsource switch 102 will be closed and a voltage will be fed to therespective parts of the circuit. In the initial state, as the switch 114(See FIG. 1) is closed, a low current will flow to the electromagnet 117through the resistor 137 (See FIG. 22) and the electromagnet 117 will beexcited. The magnetic force generated in the electromagnet 117 at thistime will be so small as not to attract the armature 17. On the otherhand, the locking lever 32 will form a magnetic circuit of the bend 32b,bent part 32b", core 117a, yoke 117b and base portion 32b' for theelectromagnet 117 and will be rotated counterclockwise when anattraction capable of overcoming the weak spring 34 is given by theelectromagnet 117. Therefore, at the time of the shutter release, if itis sensed whether the locking lever 32 rotates counterclockwise or not,it will be able to be judged whether the current source battery 101 isthe usable condition or not. When the voltage of the current sourcebattery 101 is sufficient and a current above a predetermined levelflows through the electromagnet 117, the locking lever 32 will rotatecounterclockwise as described above, the arm 32a will retreat from themoving track of the bend 2e as shown in FIG. 17 and therefore therelease lever 2 will be able to be further pushed down. When the currentflowing through the electromagnet 117 is below the predetermined level,as shown in FIG. 18, the locking lever 32 will remain to have the arm32a in contact with the bend 1l, the arm 32a will remain present withinthe moving track of the bend 2e and therefore the release lever 2 willbe no longer able to be further pushed down. Further, if a nonmagneticbody portion 117a' is provided in the part opposed to the bent portion32b" of the bend 32b, an air gap will be made within the above mentionedmagnetic circuit, the magnetic flux passing through the magnetic pathwill reduce and therefore the reduction of the magnetic flux laterattracting the armature will be able to be made low.

By the way, if the output terminal 107e of the window comparator 107 isconnected also to the output terminal 115a of the comparator 115 asshown by the chain line in FIG. 22, the release will be able to belocked simultaneously with the camera-shake warning. Also, the lockinglever 32 can be borne on the release lever 2. In this case, depending onwhether the locking lever 32 is attracted by the electro-magnet 117 ornot, a part of the locking lever 32 will not be locked or will be ableto be locked with a fixed member not illustrated. Here, in case thelocking lever 32 is attracted by the electromagnet 117, the bent portion32b" will move to slide on the core 117a as the release lever 2 ispushed down. However, if the bent portion 32b" is made to be finallyopposed to the nonmagnetic body portion 117a', the same effect as isdescribed above will be obtained. Further, in case the current sourcefor the shutter controlling circuit is used also to charge the maincapacitor of the flashing device in a camera having a flashing devicebuilt in, the current source voltage will drop while charging the maincapacitor and therefore the release locking mechanism will operate thesame as is described above.

We claim:
 1. An electric shutter device provided with an electricself-timer comprising:a shutter plate, a release member movablysupported on said shutter plate, a closing drive member movablysupported on said shutter plate and capable of moving between its cockedposition and its uncocked position and capable of being locked in thecocked position by said release member, a timer lever rotatablysupported on said shutter plate and capable of locking said closingdrive member in the initial period of the movement of said closing drivemember from its cocked position to its uncocked position, an armaturelever supported rotatably on said shutter plate and operativelyconnected with said timer lever, an electromagnet mounted on saidshutter plate and capable of attracting said armature lever, an exposuretime controlling circuit having an output terminal thereof connected tosaid electromagnet through a first resistor, a current amplifyingcircuit having an output end thereof connected to said electromagnet tomake a large current instantaneously flow to said electromagnet, a pulsegenerating circuit having an output terminal thereof connected to theinput terminal of said curent amplifying circuit, a self-timer delayingcircuit having an output terminal thereof connected to the inputterminal of said pulse generating circuit, and a current source switcharranged adjacently to said release member and capable of feeding acurrent to said electromagnet through said exposure time controllingcircuit and first resistor by the initial motion of said release member,said current being for the purpose of causing said electromagnet togenerate a magnetic force insufficient to attract said armature leverwhen said armature lever is apart from the attracting surface of saidelectromagnet but sufficient to keep said armature lever in theattracted state when said armature lever is in contact with theattracting surface, the locking of said closing drive member by saidtimer lever being released by said armature lever when said armaturelever is attracted by a large magnetic force generated in saidelectromagnet by a large current fed instantaneously to saidelectromagnet when the operation of said self-timer delaying circuitends, said closing drive member being moved to start the shutter openingoperation and becoming immediately locked again by said armature leverhaving been attracted by said electromagnet, and said armature leverbeing rotated to release the locking of said closing drive member bysaid armature lever when a proper exposure time lapses and a current tosaid electromagnet is interrupted by the operation of said exposure timecontrolling circuit, said closing drive member being again moved toclose the shutter.
 2. An electric shutter according to claim 1 whereinsaid self-timer delaying circuit includes a first switch arrangedadjacently to said closing drive member, and said delaying circuit isoperated when said first switch is opened by the initial motion of saidclosing drive member.
 3. An electric shutter device according to claim 1wherein said self-timer delaying circuit consists of a capacitorconnected in parallel with said first switch, a second resistorconnected in series to said capacitor and a third resistor connectablein parallel with said second resistor through a second switch, and twodelay times of different lengths can be obtained by switching saidsecond switch, one of said two delay times being a settable self-timerdelay time and the other being a delay time required to halt the shutteropening operation for a predetermined time after the camera releaseoperation.
 4. An electric shutter device according to claim 3 furthercomprisinga manually settable timer setting lever rotatably supported onsaid shutter plate and capable of taking its first position and itssecond position, and a timer resetting lever connected to said timersetting lever and engaged with said timer lever, said second switchbeing opened by said timer setting lever and being closed through saidtimer resetting lever and timer setting lever when said timer lever isattracted by said electromagnet.